Conventionally, imaging devices employing an electrophotographic imaging process are known. One type of imaging device is a printer which can print an image on a continuous sheet, such as a fan-fold sheet. The fan-fold sheet is provided with feed holes at its sides, and perforations which define segments (pages) of the sheet. The fan-fold sheet has conventionally been used in a line printer.
In the electrophotographic printer using a continuous sheet, if the sheet is nipped between a heat roller and press roller in a fixing device, and the sheet is not being fed, the portion of the sheet nipped between the heat roller and the press roller will be overheated. Thus, the nipped portion of the sheet may be discolored or scorched. In order to avoid this problem, the electrophotographic printer has been so constructed that the heat roller and the press roller are detached from each other so that the sheet is not nipped therebetween after the printing operation is finished.
If the printer is constructed as above, however, when the printing is restarted, the heat roller and the press roller which are separated from each other will contact the sheet nipped therebetween. If the heat roller and the press roller nip the continuous sheet, the portion of the sheet which contacts the heat roller is overheated as mentioned above. Further, if the sheet has an unfixed toner image the image may be smudged or become uneven since the portion of the press roller, which contacts the heat roller has a higher temperature than the other portion of the press roller.